As requested I have sent an email to support regarding this but have had no reply or acknowledgement so far.

I'm still abit confused by the documentation or the answer, it isn't clear to me whether I should increase the matchingThreshold on the NMatcher to reduce FFR's or vice versa. Want to be clear I'm talking about attribute on the NMatcher, not the result score returned by the matcher (If the score is greater than zero we accept it as a match).

Also what I'm finding the FFR rate reduces if I set to NMatacher.matchingThreshold to 6, but I still get FFR's. So I tried to increase the NMatcher.matchingThreshold to 24 but this only increases the number of FFR's again!

monkeyhandz wrote:As requested I have sent an email to support regarding this but have had no reply or acknowledgement so far.

The e-mail reply could take up to 2 business days. We also have different time zone that could cause time for e-mail response.The e-mail has been answered to you about half an hour ago.

monkeyhandz wrote:I'm still abit confused by the documentation or the answer, it isn't clear to me whether I should increase the matchingThreshold on the NMatcher to reduce FFR's or vice versa. Want to be clear I'm talking about attribute on the NMatcher, not the result score returned by the matcher (If the score is greater than zero we accept it as a match).Also what I'm finding the FFR rate reduces if I set to NMatacher.matchingThreshold to 6, but I still get FFR's. So I tried to increase the NMatcher.matchingThreshold to 24 but this only increases the number of FFR's again!

If the score matched between templates is lower than the matching threshold set, 0 is returned. Otherwise, the score is returned.For example:• If you set matching threshold to 0, all the templates that matches with score above 0 will be returned.• If you set matching threshold to 24, all the templates that matches with score 24 or more will return the score that it matched with.• If you set matching threshold to 48, all the templates that matches with score 48 or more will return the score that it matched with.• And so on.The higher is the matching score, the higher is the probability that the fingerprint is of the same person.The higher is the matching threshold set, the lower is the FAR (false acceptance rate) but the higher is the FRR (false rejection rate).

There is also a formula provided in the documentation how to calculate false acceptance probability of your database:(1-(1-FAR/100)^N)*100, where N - DB sizeFor example:If FAR=0.001% then probability that false acceptance situation will occur during 1:N identification (where N=10 000) is1-(1-0.00001)^10000=9.52%.If FAR=0.0001% then probability that false acceptance situation will occur during 1:N identification (where N=10 000) is1-(1-0.000001)^10000=1.00%.

You have sent the templates. They seem to be partially scanned. For example, bottom of the fingerprint scanned, template extracted and enrolled to the database. Then the top of the fingerprint is scanned, template extracted and sent for matching. As templates contains features of different fingerprint's parts, they do not have many features set that could be matched. This is why low score is returned (like 6 or 10). At least not it looks like you are trying to match different parts of the fingerprint.It is needed to get the fingerprint images to be able to tell more.

How can we implement a way to locate a person in an Oracle database, knowing only their enrolled fingerprint ?

thanks in advance.

Hello,

as you wrote, you are using VeriFinger Extended 6.4. The current version is 6.5 and I would recommend to upgrade to latest one.In any case as you are using the Extended Version of the VeriFinger SDK, then you have a possibility to use the NServer, a ready-to-use matching server. NServer supports the Oracle database. So you can configure the NServer to use the Oracle table with enrolled fingerprint templates (extracted from fingerprint images). Once it is done and the NServer is running you can run the client application, which will send a scanned fingerprint to NServer for the identification. After that, if the finger exists in the database, the NServer will return the id of the matched template. How to send and receive tasks/results to/from the NServer is shown in AbisSample and tutorials, included in the SDK.AbisSample and NServer configuration is described in the documentation of the SDK.

I would like to know the right "formula" to go from similarity score to probabilistic score.

ThanksG.-

Hello,

Matching score represents the probability of the false acceptance. The higher the matching score is returned the smaller the probability of the false acceptance. You can set the matching threshold according to your project requirements or the field tests results. When the matching is done, the matching threshold is used in this way: if the matching score is equal or higher than the set matching threshold, then the matching score is returned as result. If during the matching the matching score is lower than the matching threshold, than the zero value is returned.More information can be found in documentation of the SDK, section "6.1.1 Matching Threshold and FAR/FRR", where you will find formula for converting score to FAR too.

guilespi wrote:Matching score obviously is NOT probability of false acceptance, since a probability value is by definition between 0 and 1, and similarity scores here are taking values like 156723, 19 and 0.

It is a FAR, but expressed in integer values. Therefore we provide the formula in documentation, which allows to convert it to % expression of the FAR.

guilespi wrote:That means if I have a "similarity score" of 64576 the FAR for that value is: 10 ^ ( score / -12) ? meaning 10 ^ (-5381) which is almost 0?

yes, this is correct, with such matching score the probability that the false acceptance happened is almost zero.

guilespi wrote:And why are you presenting a "similarity score" which is not the real probability score but a transformed value?

I have used NObjectSetParameter method like extractor to set parameter from sample code. But i have got error for invalid parameter. I couldn't find any sample code for matcher parameter. I tried in many ways. But always i have got error.Can u please give me a sample code for matcher? Thanks

nurzico wrote:I have used NObjectSetParameter method like extractor to set parameter from sample code. But i have got error for invalid parameter. I couldn't find any sample code for matcher parameter. I tried in many ways. But always i have got error.

Could you please provide detailled information how it was used and what error did you get?

I use "Neurotec Biometric 5.0 SDK " to implement a face recognition program.

I Extract face from an image and use NObjectSaveToMemoryN function to save the features.

Now , I have a problem to load the feature files for doing face recognition.

I tried to use NImageCreateFromFileEx to load the features , but it doesn't work.

How can I load these files?

Hello,

as you wrote you have saved extracted features. Features does not include the image. So it is not possible to use the function NImageCreateFromFileEx to load the extracted features. If you need to load features from the file, then you need to read it as byte array and use it for matching. You can take a look at tutorials "Verify" or "Identify", which shows how to load the binary file.

ceciliafava wrote:I am using MegaMatcher SDK but I don't have any cluster server. I need compare a template with a templates stored in a database.The tutorials that are using for .NET system web-based , use

a enrollment task before using Identify function to match candidates for find similarities.Is it neccesary to do the enrollment in memory?Thanks,

Hello,

if you do not use the matching server, then you need to do the matching locally and the templates used for matching should be in memory. In case if you are want to perform the Identification (1:N) matching, then it is needed to read all templates and insert them into engine. How to verify or identify templates is shown in the tutorials provided in the SDK.

Hi! I'm revising the codes from the Samples/Biometrics folder and any code contains a method for verification 1 to 1 and any of these are using NServer for this, these examples only described verification in local. is it possible work with NServer and Verification 1:1 ?

dicaalba wrote:Hi! I'm revising the codes from the Samples/Biometrics folder and any code contains a method for verification 1 to 1 and any of these are using NServer for this, these examples only described verification in local. is it possible work with NServer and Verification 1:1 ?

Product revision number: 120480

Hello,

Yes, it is possible. Just add "WHERE dbid=ID_YOU_WANT_TO_VERIFY_WITH" at the end of matching task.

I have tried NMatcher.PartNone , I am using NServer inside an application web based over .NETThe .NET said that the NMatcher is deprecated and PartNone doesn't exist. I need to set the parameters, one of them is NMP_MATCHING_THRESHOLD to match faces and fingers

ceciliafava wrote:I have tried NMatcher.PartNone , I am using NServer inside an application web based over .NETThe .NET said that the NMatcher is deprecated and PartNone doesn't exist. I need to set the parameters, one of them is NMP_MATCHING_THRESHOLD to match faces and fingers

Regards,

Hello,

I assume you are talking about Neurotec Biometric 5.0 SDK. In such case, please ignore that NMathcher is deprecated.To set matching threshold use:

What is the relation between match threshold and min match count threshold in respect to min match count?I am using combined fingerprint templates to match.In example, match threshold 96, min match count 2 and min match count threshold 96 Matching two combined templates each having 4 fingers.Can you please explain what is the scenario of this case for matching? I mean how min match count threshold relating with match threshold and match count for deciding whether the pair is matched or not? I am using SDK version 4.3

I have seen same type of question's answer.I know there is no limit of matching score.But is there any way to figure it out the fingerprint similarity score in percentage or any classifications?I am using combined fingerprint templates to match.My SDK version is 4.3

nurzico wrote:I have seen same type of question's answer.I know there is no limit of matching score.But is there any way to figure it out the fingerprint similarity score in percentage or any classifications?I am using combined fingerprint templates to match.My SDK version is 4.3

Sorry to ask that question again.

Hello,

No, it is not possible to convert the similarity score into percentage.

nurzico wrote:What is the relation between match threshold and min match count threshold in respect to min match count?I am using combined fingerprint templates to match.In example, match threshold 96, min match count 2 and min match count threshold 96 Matching two combined templates each having 4 fingers.Can you please explain what is the scenario of this case for matching? I mean how min match count threshold relating with match threshold and match count for deciding whether the pair is matched or not? I am using SDK version 4.3

Hello,

i.e. you have 4 fingerprint template. i.e. If the Minimal Match count is set to two, then during matching initially only 2 fingers from 4 fingers template will be used for matching and if their score will be higher then the set Minimal Match Threshold, then other two fingers will be matched too. Otherwise, if the score will be lower than the set Minimal Match Threshold then other two fingers are not matched.This helps to speed up the matching, but could result in lower accuracy.

nurzico wrote:What is the relation between match threshold and min match count threshold in respect to min match count?I am using combined fingerprint templates to match.In example, match threshold 96, min match count 2 and min match count threshold 96 Matching two combined templates each having 4 fingers.Can you please explain what is the scenario of this case for matching? I mean how min match count threshold relating with match threshold and match count for deciding whether the pair is matched or not? I am using SDK version 4.3

Hello,

FingersMinMatchedCount and FingersMinMatchedCountThreshold are used for customized matching. Please refer to the documentation of the SDK, section “Cuztomized matching”.

nurzico wrote:I have seen same type of question's answer.I know there is no limit of matching score.But is there any way to figure it out the fingerprint similarity score in percentage or any classifications?I am using combined fingerprint templates to match.My SDK version is 4.3

Sorry to ask that question again.

Hello,

No, there is no possibility to convert matching threshold to percentage value.As you may know the matching threshold represents the probability that the false acceptance happened. The higher the returned matching score, the lower the probability that the false acceptance happened.Please read documentation, section “Matching Threshold and FAR/FRR” to understand better.

you need to have Fast Face Matcher license activated on that machine.In your code you need to obtain license for "Biometrics.FaceMatchingFast" component.Also you need to set FacesMatchingSpeed parameter in the NBiometricClient to High.

Now, I have try using AbisSample (AbisSampleWX.exe) for face detection but still don"t understand how to enroll the facial image files taken from image file for officer ID cards to train AbisSample to learn about the faces of 18 men and women in my office and then detect the facial image files taken from video clips which has been kept in various directories. AbisSample does not as straightforward as FacialSample program (FacesSampleWX.exe) at all. If you can explain how to use AbisSample for proper facial detection, I would be appreciated.

Furthermore, the suggestion on how to modify source codes of FacialSample program to allow straightforward facial detection with function to readjust (lower) Quality Threshold to make FacialSample program to learn about the facial information taken from ID cards to detect facial image files taken from video clips to identify whether the facial image files taken from video clips is one of 18 men and women in my office. If FacesSample program is written in C or C++, I would be greatly appreciated.

Wisarut wrote:Now, I have try using AbisSample (AbisSampleWX.exe) for face detection but still don"t understand how to enroll the facial image files taken from image file for officer ID cards to train AbisSample to learn about the faces of 18 men and women in my office and then detect the facial image files taken from video clips which has been kept in various directories. AbisSample does not as straightforward as FacialSample program (FacesSampleWX.exe) at all. If you can explain how to use AbisSample for proper facial detection, I would be appreciated.

Furthermore, the suggestion on how to modify source codes of FacialSample program to allow straightforward facial detection with function to readjust (lower) Quality Threshold to make FacialSample program to learn about the facial information taken from ID cards to detect facial image files taken from video clips to identify whether the facial image files taken from video clips is one of 18 men and women in my office. If FacesSample program is written in C or C++, I would be greatly appreciated.

Method NBiometricClient.Verify It just work in server, and after some time, the performance is low, takes longer to process. It starts fast and after turns slow. Why? I"m doing multiples verification within loop.

Which is the way to do the multiple verification without using a lot of memory? the memory machine is increasing quite.

Jorgtdna wrote:Method NBiometricClient.Verify It just work in server, and after some time, the performance is low, takes longer to process. It starts fast and after turns slow. Why? I"m doing multiples verification within loop.

Which is the way to do the multiple verification without using a lot of memory? the memory machine is increasing quite.

Verification is for 1:1 matching. Identification - 1:many matching.If you are using Verify to do 1:many matching, it will always perform few times slower than Identify, because identification is optimized to do 1:N matching and verification is not. Use identification to do 1:N matching.

The template used consists of the Face and two fingerprints; everything is working fine, except that when I try to identify someone with those 3 biometrics, I would expect that these are fusioned and the result be unique.Even if I raise the MatchingThreshold of the BiometricClient object, in the vast majority it is returning more than one match.In previous versions there was the NMatcher with the NMFusionType parameter, now the NMatcher object and all of its properties are deprecated.

I think that the default is Detect by Face then fuse, how can I change this so the result is created with all of the biometrices fused?

The template used consists of the Face and two fingerprints; everything is working fine, except that when I try to identify someone with those 3 biometrics, I would expect that these are fusioned and the result be unique.Even if I raise the MatchingThreshold of the BiometricClient object, in the vast majority it is returning more than one match.In previous versions there was the NMatcher with the NMFusionType parameter, now the NMatcher object and all of its properties are deprecated.

I think that the default is Detect by Face then fuse, how can I change this so the result is created with all of the biometrices fused?

Thanks

Hello,

the default fusion mode is "FuseAllways".If you are getting issues with matches, then provide details on the issue with used parameters and templates to support@neurotechnology.com.

How template get saved in SQLite database becasue biometricclient.setSQLiteDatabseConnection(String args0) will create only file at specified filename.Is that this method also saves Template in database??Because we are not passing any template.I not able to understand.

Because when I run abis-sample code during enrolment template get saved in database, Is my observation right ?